package zuoye;
import java.util.ArrayList;
public class zuoye6 {
	 public static void main(String[] args) {
	        ArrayList<Integer> list = new ArrayList<>();
	        list.add(100);
	        list.add(200);
	        list.add(300);
	        String result = printArrayList(list);
	        System.out.println(result);
	    }
	    private static String printArrayList(ArrayList<Integer> list) {
	        String result = "{";
	        for (int i = 0; i < list.size(); i++) {
	            result += list.get(i);
	            if (i != list.size() - 1) {
	                result += "@";
	            }
	        }
	        result += "}";
	        return result;
	    }
}
